Pubsub仿真器重新发送已确认的消息

Question

我创建了一个订户客户端，以侦听来自pubsub仿真器的消息。当我向pubsub发布500多条消息时。尽管已经确认了这些消息，但订阅者客户端仍然收到了消息。

我正在使用python 3。

共有3个课程：

A类：订阅者客户端侦听来自pubsub仿真器的消息

B类：用于将消息存储到云存储的对象

C类：用于将消息提取并插入到SQL表中的对象

from google.cloud import pubsub_v1
import B
import C

class A(object):
    def receive_messages(self,project_id, subscription_name):

        subscriber = pubsub_v1.SubscriberClient()

        subscription_path = subscriber.subscription_path(
                            project_id, subscription_name)

        def callback(message):
            print('Received message: {}'.format(message))

            B_obj = B()
            storing_status = B_obj.storing_to_cloud_drive()

            if storing_status:
                message.ack()
                print('Message is acked')

                C_obj = C()
                C_obj.extract_and_insert_to_sql_table()

            else:
                message.nack()
                print('Message is nacked')

        subscriber.subscribe(subscription_path, callback=callback)

        print('Listening for messages on {}'.format(subscription_path))
        while True:
            time.sleep(60)